Non-Invasive Hemoglobin Measurement: A Great Blessing to the Rural Community

Introduction

India has a very high prevalence of anemia, and some estimates suggest that 20-40% of maternal deaths in India are caused by anemia. About half of the maternal deaths due to anemia across the world occur in India (1).

Although there have been efforts in the past couple of decades to control anemia in pregnancy and during lactation, they do not seem to have been effective. Nutritional anemia is still a major public health problem (2).

Low dietary intake of iron and folic acid is a significant factor in anemia in pregnant women and children, and supplements of these would go a long way in preventing morbidity and maternal mortality. Studies of anemia in rural communities are difficult because of the invasive nature of the test, the costs involved, etc.

We describe a non-invasive method of hemoglobin measurement that was developed at the Karunya University.

The Method

Red blood cells absorb light of wavelengths between 650 and 900 nm. This is in the range of red and infrared light. The commonly used sensor for measuring oxygen saturation and pulse rate is used for measurement. The reflected light from the sensor is collected and amplified, and then analyzed using LabView software. Figure 1 shows the setup.

Figure 1: The arrangement

The experimental setup is shown diagrammatically in Figure 2.

Figure 2: Block diagram of the proposed hemoglobin measuring system

Complex calculations are necessary because the colour and absorption of oxygenated and de- oxygenated Hemoglobin varies. This is not a problem with chemical testing, as the colour is dependant solely on the amount of available hemoglobin. Several filters and calculations are necessary to take care of the variations in colour and the amount of soft tissue between the light source and the sensor. Sixty-three patients and volunteers had their Hemoglobin testing at the Laboratory of the SEESHA Karunya Hospital. ...